U.S. patent application number 13/315899 was filed with the patent office on 2012-07-05 for doctor blade holder.
This patent application is currently assigned to KADANT INC.. Invention is credited to Allen Brauns, Robert Johnson, David Leeman.
Application Number | 20120167330 13/315899 |
Document ID | / |
Family ID | 45390218 |
Filed Date | 2012-07-05 |
United States Patent
Application |
20120167330 |
Kind Code |
A1 |
Leeman; David ; et
al. |
July 5, 2012 |
DOCTOR BLADE HOLDER
Abstract
A doctor blade holder system is disclosed that includes a doctor
blade holder that includes a doctor blade receiving region for
receiving a doctor blade, and an actuation system for causing the
doctor blade receiving region to be selectively moved toward or
away from a roll surface by rotating the doctor blade holder about
a first axis, wherein the doctor blade holder system is generally
circular shaped in cross-sectional area and wherein the first axis
is generally centrally locate with the generally circular
cross-sectional area.
Inventors: |
Leeman; David; (Worcester,
MA) ; Brauns; Allen; (Sturbridge, MA) ;
Johnson; Robert; (Sutton, MA) |
Assignee: |
KADANT INC.
Westford
MA
|
Family ID: |
45390218 |
Appl. No.: |
13/315899 |
Filed: |
December 9, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61421751 |
Dec 10, 2010 |
|
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|
Current U.S.
Class: |
15/300.1 ;
15/256.53 |
Current CPC
Class: |
D21G 3/005 20130101;
B41P 2235/21 20130101 |
Class at
Publication: |
15/300.1 ;
15/256.53 |
International
Class: |
B21B 45/02 20060101
B21B045/02; A47L 9/00 20060101 A47L009/00 |
Claims
1. A doctor blade holder system comprising: a doctor blade holder
that includes a doctor blade receiving region for receiving a
doctor blade, and actuation means for causing the doctor blade
receiving region to be selectively moved toward or away from a roll
surface by rotating the doctor blade holder about a first axis,
wherein the doctor blade holder system is generally circular shaped
in cross-sectional area and wherein the first axis is generally
centrally locate with the generally circular cross-sectional
area.
2. The doctor blade holder system as claimed in claim 1, wherein an
axis of rotation of the doctor blade holder is generally centrally
located in the generally circular cross-sectional area.
3. The doctor bade holder system as claimed in claim 1, wherein
said doctor blade holder includes an internal plenum that is
coupled to a vacuum source.
4. The doctor blade holder system as claimed in claim 3, wherein
said doctor blade holder further includes a pad adjacent at least
one opening that communicates with the internal plenum.
5. The doctor blade holder system as claimed in claim 1, wherein
said doctor blade holder includes loading and unloading tubes
within the doctor blade holder for alternating urging the doctor
blade toward or away from the roll.
6. The doctor blade holder system as claimed in claim 1, wherein
said doctor blade holder system includes a fixed structure that
receives the doctor blade holder, and wherein the fixed structure
has a generally circular shaped cross-sectional area.
7. The doctor blade holder system as claimed in claim 6, wherein
said doctor blade holder is pivotally coupled to said fixed
structure by integrally formed coupling structures.
8. The doctor blade holder system as claimed in claim 6, wherein
said fixed structure is secured to a frame by clamps at each end of
the doctor blade holder system.
9. The doctor blade system as claimed in claim 6, wherein said
fixed structure includes an internal plenum that is coupled to a
vacuum source.
10. A doctor blade holder system comprising: a doctor blade holder
that includes a doctor blade receiving region for receiving a
doctor blade, and actuation means for causing the doctor blade
receiving region to be selectively moved toward or away from a roll
surface by rotating the doctor blade holder about a first axis,
wherein the first axis passes through a generally central region of
the doctor blade holder.
11. The doctor blade holder system as claimed in claim 10, wherein
said doctor blade holder is generally circular in cross-sectional
area.
12. The doctor bade holder system as claimed in claim 10, wherein
said doctor blade holder includes an internal plenum that is
coupled to a vacuum source.
13. The doctor blade holder system as claimed in claim 10, wherein
said doctor blade holder further includes a pad adjacent at least
one opening that communicates with the internal plenum.
14. The doctor blade holder system as claimed in claim 10, wherein
said doctor blade holder includes loading and unloading cylinders
for alternating urging the doctor blade toward or away from the
roll.
15. A doctor blade holder system comprising: a doctor blade holder
that includes a doctor blade receiving region for receiving a
doctor blade; a fixed structure that pivotally receives a portion
of the doctor blade holder at either longitudinal end of the doctor
blade holder; and actuation means for causing the doctor blade
receiving region to be selectively moved toward or away from a roll
surface by rotating the doctor blade holder about a first axis,
wherein the first axis passes through both the doctor blade holder
and the fixed structure.
16. The doctor blade holder system as claimed in claim 15, wherein
said fixed structure is generally circular in cross-sectional
area.
17. The doctor bade holder system as claimed in claim 15, wherein
said fixed structure includes an internal plenum that is coupled to
a vacuum source.
18. The doctor blade holder system as claimed in claim 17, wherein
said fixed structure further includes a pad adjacent at least one
opening that communicates with the internal plenum.
19. The doctor blade holder system as claimed in claim 15, wherein
said fixed structure includes loading and unloading tubes within
the fixed structure for alternating urging the doctor blade toward
or away from the roll.
20. The doctor blade holder system as claimed in claim 15, wherein
said fixed structure includes integrally formed cross-machine
direction chambers.
Description
PRIORITY INFORMATION
[0001] The present application claims the benefit of U.S.
Provisional Patent Application Ser. No. 61/421,751 which was filed
on Dec. 10, 2010, all of which is incorporated herein in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to doctors for processing moving
surfaces in manufacturing systems involving rolls, webs or sheets
such as papermaking systems, fiber and textile processing systems
and aluminum/steel processing, and is concerned in particular with
an improved design that simplifies construction for certain
applications yet meets the high demands of doctoring systems.
[0004] 2. Description of the Prior Art
[0005] Many roll cleaning and sheet shedding applications on web
handling applications such as paper and textile processing machines
involve blade support devices commonly referred to as doctor blade
holders for supporting blades such as doctor blades, creping blades
and scraping blades.
[0006] Certain prior art doctor blade holders include a top plate
(to which a doctor blade is joined), a bottom plate, and a mounting
and adjustment assembly between the top and bottom plates. The
bottom plate is mounted on a doctorback, which is a heavy-duty beam
that spans the paper machine width. The rear portion of a doctor
blade is received into the doctor blade holder that supports the
blade in a pre-determined position relative to a surface to be
cleaned. The doctor blade holder works in concert with the doctor
blade to apply the working edge of the doctor blade, found on the
blade's front portion, to an adjacent moving surface such as a
roll.
[0007] FIG. 1 for example, shows a prior art doctoring apparatus 10
that is adjacent to the surface of a roll 12. The roll rotates
about an axis A.sub.r, and the doctoring apparatus includes a
doctorback 14 that is rotatable about an axis A.sub.db, which is
parallel to the axis A.sub.r. A doctor blade holder 16 is shown
supported on a beam 18, which forms part of the doctorback. The
doctor blade holder 16 includes has top plate 20 and a bottom plate
22 that are joined by a mounting and adjustment assembly. A doctor
blade 24 is received within a lower jaw opening 26 on the underside
of the top plate 20.
[0008] With further reference to FIG. 2, the mounting and
adjustment assembly includes a plurality of top plate brackets 28
and a plurality of bottom plate brackets 30 that are mutually
joined together by a pivot rod 32. The mounting and adjustment
assembly also includes a loading tube 34 and an unloading tube 36
that may each be alternately increased or decreased in size by
adjusting an amount of fluid within each tube to effect a limited
rotation of the top plate with respect to the axis that is the
central axis of the pivot rod 32. This limited rotation permits the
doctor blade 24 to engage the roll 12 to effect doctoring, or to
disengage the roll 12. A piston/cylinder unit 38 acts via a crank
arm 39 to rotate the doctorback 14 about axis A.sub.db in order to
provide gross positioning of the doctor blade 24 near and away from
the roll surface.
[0009] Doctor blade holders are typically assemblages of several
discrete components, many of which (such as the brackets 28 and 30)
are duplicated within the assembly dozens or scores of times, and
must be riveted or otherwise fastened to the plates 20 and 22
respectively. This multiplicity of components has allowed holder
manufacturers to custom-build holders to match the custom-built
paper machines. These multiple repeating components, however,
require substantial assembly time, which increases holder cost and
opportunities for assembly errors.
[0010] Other prior art doctor blade holders, such as disclosed in
U.S. Pat. No. 6,447,646, include an extruded or pultruded holder
frame 40 that is pivotally mounted to an extruded or pultruded
bearer 42 via a jointed bearing assembly 44 as shown in FIG. 3. The
jointed bearing assembly 44 includes a joint sleeve 46 (e.g., in
holder frame 40) that couples with a unified axle 48 (e.g., in the
bearer 42). A doctor blade 50 is coupled to a blade holder 52,
which is attached to the holder frame 40. Loading devices 54 and 56
apply positive and negative loading forces to the doctor blade 50
with respect to the roll 58. Separating the holder frame 40 from
the bearer 42, however, requires sliding the holder frame 40 and
the bearer 42 with respect to one another along the full elongated
dimension of the doctoring apparatus, which may be a several or
more meters in width. This may not only be awkward and/or
impractical, but it may further require that the doctoring
apparatus be moved to a more spacious location. U.S. Patent
Applications Publication Nos. 2006/0180291 and 2006/0289141, as
well as U.S. Pat. No. 6,942,734 also disclose doctor blade holder
systems that include integrally formed mounting elements that
extend along the elongated dimension of the doctor blade.
[0011] Further prior art blade holder systems, such as for example
disclosed in U.S. Patent Application Publication No. 2006/0054293,
include a base plate 60 and a cover plate 62 having a finger device
64 that receives a scrapping blade 66 as shown in FIG. 4. The base
plate 60 and cover plate 62 are pivotally coupled together by a
bearing tube 68 mounted on the based plate 60, which is received
within a square tube 70 mounted to the underside of the cover plate
62. The square tube 70 is disclosed to be installed in segments in
a direction perpendicular to the plane of the drawing in order to
impair the resilience of the cover plate 62 as little as possible.
The rotational position of the cover plate 62 with respect to the
base plate 60 is adjustable by the inflation/deflation of an air
pressure hose 72 in cooperation with a spring 74. Separating the
cover plate 62 from the base plate 60, however, requires sliding
the cover plate 62 and the base plate 60 with respect to one
another along the full elongated dimension of the doctoring
apparatus, which may be a several or more meters in width.
[0012] An objective of the present invention is to provide an
improved holder design that greatly reduces the number of
components and therefore the cost, yet satisfies the demanding
strength requirements of doctor blade holder systems.
SUMMARY OF THE INVENTION
[0013] In accordance with an embodiment, the invention provides a
doctor blade holder system that includes a doctor blade holder that
includes a doctor blade receiving region for receiving a doctor
blade, and an actuation system for causing the doctor blade
receiving region to be selectively moved toward or away from a roll
surface by rotating the doctor blade holder about a first axis,
wherein the doctor blade holder system is generally circular shaped
in cross-sectional area and wherein the first axis is generally
centrally locate with the generally circular cross-sectional
area.
[0014] In accordance with another embodiment, the invention
provides a doctor blade holder system including a doctor blade
holder that includes a doctor blade receiving region for receiving
a doctor blade, and an actuation system for causing the doctor
blade receiving region to be selectively moved toward or away from
a roll surface by rotating the doctor blade holder about a first
axis, wherein the first axis passes through a generally central
region of the doctor blade holder.
[0015] In accordance with a further embodiment, the invention
provides a doctor blade holder system including a doctor blade
holder that includes a doctor blade receiving region for receiving
a doctor blade, a fixed structure that pivotally receives a portion
of the doctor blade holder at either longitudinal end of the doctor
blade holder, and an actuation system for causing the doctor blade
receiving region to be selectively moved toward or away from a roll
surface by rotating the doctor blade holder about a first axis,
wherein the first axis passes through both the doctor blade holder
and the fixed structure.
[0016] A primary object of the present invention is to provide a
simplified doctoring structure designed to fit into the narrow
confines of compact web and web-like processing machines while
still providing control of doctor blade loading as well as
efficient and safe access to the doctor blade for removal and
replacement.
[0017] Another object is to integrate the one or more renewable
debris collection systems into the holder body.
[0018] Another object is to integrate within the same holder body
uniform vacuum pressure means and directing said vacuum to the area
near the blade-roll contact line in order to remove debris that is
known to accumulate there.
[0019] Another object is to provide within the doctor body, means
for attaching journals and other external loading mechanisms
without resort to welding or other machine work.
[0020] Another object is to provide within the doctor design a
two-tube blade loading and unloading system familiar to web
processing machine operators and easily integrated with
pre-existing equipment.
[0021] Another object is to provide significant doctor weight
reduction by forming at least one of the two pieces with a
substantially hollow cross-section.
[0022] Another object is to incorporate groups of one or more
holder components into formed pieces via extrusion processes
thereby reducing assembly part counts and associated labor, as
compared to the multiple part assembly processes of prior art
holders.
[0023] Another object is to provide a doctor blade retention
feature formed directly into the single-component doctor
structure.
[0024] Another object is to provide a blade retention means that
efficiently conveys the load imposed on the doctor blade by the
doctored surface to the doctor's external supports.
[0025] Another object is to provide a debris accumulation region
formed into the doctor structure.
BRIEF DESCRIPTION OF THF. DRAWINGS
[0026] The following description may be further understood with
reference to the accompanying drawings in which:
[0027] FIG. 1 shows an illustrative diagrammatic side view of a
prior art doctor blade holder attached to a doctorback;
[0028] FIG. 2 shows an illustrative diagrammatic enlarged side view
of the doctor blade holder of FIG. 1;
[0029] FIGS. 3 and 4 show illustrative diagrammatic side views of
further prior art doctor blade holders;
[0030] FIG. 5 shows an illustrative diagrammatic side view of a
doctor blade holder in accordance with an embodiment of the present
invention;
[0031] FIG. 6 is an illustrative diagrammatic partial
cross-sectional view of the doctor blade holder of FIG. 5 showing
the integrated blade retention, journal mounting and component
fastening features;
[0032] FIG. 7 is an illustrative diagrammatic top perspective view
of the doctor and blade assembly of FIGS. 5 and 6;
[0033] FIG. 8 shows an illustrative diagrammatic view of doctoring
system using the doctor blade holder of FIGS. 5-7 using air
cylinders to rotate the doctor blade holder toward or away from a
roll;
[0034] FIGS. 9 and 10 are illustrative diagrammatic enlarged views
of portions of the system of FIG. 8;
[0035] FIG. 11 shows an illustrative diagrammatic side sectional
view of a doctor blade holder that includes an internal vacuum
plenum and is adapted to receive a pad in accordance with another
embodiment of the invention;
[0036] FIG. 12 shows an illustrative diagrammatic oblique view of
the doctor and doctor blade holder of FIG. 11;
[0037] FIG. 13 shows an illustrative diagrammatic top perspective
view of the doctor blade and doctor blade holder of FIGS. 11 and
12;
[0038] FIG. 14 shows illustrative diagrammatic side view of a
doctoring system in accordance with a further embodiment of the
invention having an integrated mounting means to receive a
replaceable debris collection device;
[0039] FIG. 15 is shows an illustrative diagrammatic side sectional
view of a doctor blade holder in accordance with a further
embodiment of the present invention wherein the doctor is rotated
relative to a fixed structure via internal pressurized tubes in
order to load the doctor blade tip to a surface, and to retract the
doctor blade away from the surface;
[0040] FIG. 16 shows an illustrative diagrammatic partial side view
of the doctor blade holder of FIG. 15 mounted in a doctoring
assembly;
[0041] FIG. 17 shows an illustrative diagrammatic partial side
perspective view of the system of FIG. 16;
[0042] FIG. 18 shows an illustrative diagrammatic enlarged view of
a portion of the mounting structure of the system of FIGS. 16 and
17; and
[0043] FIG. 19 shows an illustrative diagrammatic side sectional
view of a doctor blade holder that includes an internal vacuum
plenum and is adapted to receive a pad in accordance with a further
embodiment of the invention.
[0044] The drawings are show for illustrative purposes only.
DETAILED DESCRIPTION
[0045] The present invention incorporates the functions of the
doctor blade holder and the doctorback into a single doctoring
element, substantially reducing complexity, manufacturing cost, and
weight.
[0046] With reference initially to FIG. 5, a doctor blade holder
system 100 is shown adjacent to the surface 102 of a roll 104. The
roll 104 rotates about an axis A.sub.1, and the doctoring apparatus
includes a doctor blade holder 106 that is rotatable about an axis
A.sub.2, which is parallel to axis A.sub.1. The doctor blade
retention region 108 in accordance with the present embodiment is
included as an integral part of the doctor blade holder 106 as
further shown in FIGS. 6 and 7. The blade retention region 108
defines a slot 110 for receiving the rear edge of a doctor blade
112. The forward edge of the doctor blade is applied to the surface
102 of the roll 104 to effect doctoring.
[0047] The doctor blade holder 106 includes a doctor blade holder
core 114 that is formed, preferably by extrusion, from metal, such
as stainless steel alloys such as 300 series, or aluminum alloys
such as series 6000, the latter being preferred. Such aluminum
alloys may be treated with one or more protective coatings as is
well known to those skilled in the art.
[0048] With reference to FIG. 6, the doctor blade holder 106 is
shown in partial cross-section to illustrate that the doctor blade
holder core 114 is hollow and includes internal features such as
cross-machine chambers 116, component fastening structures 118 and
a journal bore 120. Also shown are the doctor blade 112 and the
doctor blade retention region 108. The component fastening features
118 provide that the doctor blade holder core 114 may be attached
to cover plates 122 and 124 at either end of the doctor blade
holder core 114 as shown in FIG. 8. Mating portions of the cover
plates 122 and 124 engage the component fastening features 118 of
the doctor blade holder core 114. The cross machine chambers 116
and journal bore 120 reduce the weight (and therefore inertia) of
the doctor blade holder without compromising its rigidity and
strength. In further embodiments, as discussed below, the cross
machine chambers 116 and journal bore 120 may further be used to
provide fluid (such as vacuum) to an area proximate the doctor
blade 112.
[0049] FIG. 7 shows the doctor blade holder core 114 and blade 112
in perspective view illustrating the hollow cross machine chambers
116, integrated fastening structures 118 and the journal bore 120.
Again, each cover plate 122, 124 may be attached to the integral
fastening structures 118, and a journal bearing 126 that is
attached to a bearing bracket 128 may align with the journal bore
120 for receiving a journal as further shown in FIGS. 9 and 10.
[0050] FIGS. 8-10 also show a mounting assembly by which the doctor
blade holder 106 is mounted on a fixed machine frame 134 and
positioned adjacent a roll 104. The doctor blade 112 is directed
downward and is visible in FIG. 10. As shown, one or two air
cylinders 130 (one is shown) are employed to selectively drive one
or more torsion arms 130 (one is shown coupled to cover plate 122,
which is also shown in FIG. 5). Each air cylinder 130 has an
actuator rod 136 that is coupled via a Clevis 139 and pin (not
shown) to each torsion arm 132 for causing the doctor blade holder
106 to rotate, urging the front edge of the doctor blade either
toward or away from the roll surface. Applicants have found that
the generally circular cross-sectional area of the doctor blade
holder system (and in this embodiment, the doctor blade holder
itself) facilitates in providing sufficient strength and rigidity
during doctoring operations.
[0051] FIGS. 11-13 show another embodiment of the invention in
which the doctor blade holder includes a doctor blade holder core
140 that is similar to the doctor blade holder 106 of FIGS. 5-10,
except that a vacuum source is coupled to an internal plenum
providing a cross-machine vacuum chamber 142, and a series of
vacuum ports 144 (also shown in FIG. 13) that are provided in a
wall of the doctor blade holder core 140. A vacuum pad retaining
structure 146 is also provided for retaining a pad 148 adjacent the
ports 144. During use, the vacuum draws into the pad 148, debris
that becomes detached from the doctoring surface during doctoring
operations. The pad 148 may then periodically be replaced. The
remaining components of such as system are as described above with
reference to FIGS. 5-10. For example, the doctor blade holder core
140 also includes cross-machine direction chambers 150, component
fastening structures 152 and a journal bore 154 that provide
functionality as discussed above with reference to the embodiment
of FIGS. 5-10, as well as an integrally formed doctor blade
retention region 156 that defines a slot 158 for receiving a doctor
blade.
[0052] FIG. 14 illustrates a further embodiment of the invention
wherein the doctor blade holder core 160 has an integrally formed
(female) pivotal mounting structure 162 that extends along the
cross-machine direction. The mounting structure 162 receives the
extended (male) pivotal mounting structure 164 of a cleaning
assembly 166. In a preferred embodiment the cleaning assembly
contains a pad 158 that is designed to collect debris detached from
the doctored surface of the roll 170. The remaining components of
such as system are as described above with reference to FIGS. 5-10.
For example, the doctor blade holder core 160 also includes
cross-machine direction chambers 172, component fastening
structures 174 and a journal bore 176 that provide functionality as
discussed above with reference to the embodiment of FIGS. 5-10 as
well as an integrally formed doctor blade retention region that
defines a slot 178 for receiving a doctor blade.
[0053] FIG. 15 shows a cross-sectional view of a doctor blade
holder 180 of a doctor blade holder system in accordance with a
further embodiment of the invention wherein the doctor blade holder
180 includes two primary components, a first of which (a doctor
blade holder core) 182 is a doctoring core structure that is fixed
in place and contains an internal female pivoting structure 184
that extends in the cross-machine direction. The second primary
component 186 is the doctor blade holder and includes a male
pivoting structure 188 that is received within the pivoting
structure 184 of the first component 182. The second primary
component 186 also includes an integrally formed doctor blade
retaining region 200 that defines a slot 188 for receiving a doctor
blade 190 that also extends in the cross-machine direction.
[0054] The structure 182 further contains integral cross machine
structures 192 that position a blade load tube 194 and blade unload
tube 196 between the structures 192 and pressure arm 198 of the
blade holder component 186. The doctor blade 190 is brought to bear
against an adjacent surface by rotating the doctor blade retaining
region 200 of the doctor blade holder component 186
counterclockwise (as shown) by pressurizing the blade load tube 194
using a pressurized fluid, preferably air, while venting fluid
present in the blade unload tube 196. Similarly, the doctor blade
190 is retracted from an adjacent surface by rotating the blade
holder retaining region 200 clockwise by pressurizing the blade
unload tube 196 while venting the blade load tube 194. A dust
shield 202 that is preferably integrally formed with the doctor
blade holder component 186 covers the opening in the doctor blade
holder core component 182. Applicants have found that the generally
circular cross-sectional area of the doctor blade holder system
(and in this embodiment, the fixed structure 182) facilitates in
providing sufficient strength and rigidity during doctoring
operations. The doctor blade holder core component 182 also
includes cross-machine direction chambers 204, component fastening
structures 174 and a journal bore 176 that provide functionality as
discussed above with reference to the embodiment of FIGS. 5-10
[0055] As further shown in FIGS. 16-18, the fixed doctor blade
holder core component 182 of the doctor bade holder system of FIG.
15 may be clamped within a doctor bearings 210 by clamp arms 212,
214 and threaded fasteners 216, 218 at each end. The doctor
bearings 210 are secured to a frame 220 as also shown at each end.
A roll bearings 222 are is adapted to receive roll journal ends 224
of a roll 226 to be doctored.
[0056] FIG. 19 shows a further embodiment of the invention in which
the doctor blade holder system 230 is similar to the doctor blade
holder system 180 of FIGS. 15-18, except that a vacuum source is
coupled to an internal plenum 232 defined within the fixed doctor
blade holder core component 234 providing a vacuum chamber, and a
series of vacuum ports 236 (similar to those shown in FIG. 13) are
provided in a wall of the doctor blade holder core component 234.
Vacuum pad retaining structures 238 are also provided for retaining
a pad 240 adjacent the ports 236. During use, the vacuum draws
debris into the pad 240 that becomes detached from the doctoring
surface during doctoring operations. The pad 240 may then
periodically be replaced The remaining components of such as system
are as described above with reference to FIGS. 15-18 except that an
additional wall 242 is provided to define the internal plenum.
[0057] Those skilled in the art will appreciate that numerous
modifications and variations may be made to the above disclosed
embodiments without departing from the spirit and scope of the
invention.
* * * * *